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More on fluxgate

So, after designing my own, sort of curious how to make it more temperature stable. These guys did it right it seems:

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There exist a second way to do this, in that case you drive the coils into saturation halfway through the period, and 'tune' the pick up coils to the second harmonic. Somehow this seems to cancel temperature influences. In my fluxgate heating it up can make several degrees difference.

Now I see these guys drive with 15625 Hz, and I see 3 big pot cores ... could be a LC filter at 31250 Hz...

Also 3 separate 1 axis magnetometers make it much more easy to align. There is also some other patent on this, but I tried downloading the pdf from freepatentsonline.com without any luck, but

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describes some .. art, no pictures.

It looks as if I was right about the Cassini magnetometer using second harmonic, I found a Themis magnetometer paper free for download:

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it has a nice block diagram, is FPGA based, and uses the second harmonic method, uses a feedback coil.

Enough new material for more experiments. I want to see that earth magnetic field changing too:

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I am going to log the values with the current mag_pic tonight during the night, as then (hopefully) no magnets will move about in the house, this is a big problem, it picks up things very far away. Will just write a script and get status every minute or so, and parse it later.

Reply to
Jan Panteltje
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I always us

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Using your reference number, I pulled up a 15 page document with schematic block diagrams, waveforms, and lots of text.
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Reply to
lektric.dan

On a sunny day (Fri, 10 Jun 2011 08:33:51 -0700 (PDT)) it happened " snipped-for-privacy@gmail.com" wrote in :

Thank you very much! That works 100%, I have the pdf now. :-)

Reply to
Jan Panteltje

stable.

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but

pictures.

harmonic,

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method,

Why don't you use the US patent office:

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and plunk in the patent number? Not a big deal to download the free AlternaTiff prog for viewing and saving of images.

Reply to
Robert Baer

If you use the pat2pdf web site, you get all the pages in one ready- rolled file, not a bunch of single files you have to try to read with a plug-in that may or mayn't work with your browser. A single pdf is a lot easier to save, too. I've got patent files that are dozens of pages.

html/PTO/srchnum.htm

nd

Reply to
lektric.dan

stable.

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but

pictures.

harmonic,

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method,

house,

later.

Irfanview does tiffs, too.

John

Reply to
John Larkin

On a sunny day (Sun, 12 Jun 2011 19:26:15 -0700) it happened John Larkin wrote in :

Irfanfview is OK, but it needs MS bloat.

I use xv in Linux for tiff, and almost all other picture formats. I even have a special version of Xv that can display ESA files: xv-PIRL.tar.gz quote from README-PIRL: The primary PIRL enhancement provides a module (xvPVL.c) that implements the LoadPVL function. This module is designed to load any PVL (Parameter Value Language) formatted image file, but does not provide a save/write function. PVL is used by the Planetary Data System as a "standard" for the distribution of products (primarily image files, but there are other types) associated with spacecraft science missions. end quote

So, for pdf I use xpdf.

There are several more good viewer programs for Linux, all with their own features.

Reply to
Jan Panteltje

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